Telephone toll set.



I C- A. ANDERSON.

/ TELEPHUNE TOLL SEI.

' APPLICATION FIL'ED APR. 30. 19!]. 1,252,216. I Patented Jan. 1,1918.

2 SHEETS-SHEET I 3 c. A. ANDERSON.

TELEPHONE TOLL SET. APPLICATION F ILED APR. 30.1917.

n 8 I 0 mm Mama; m 32 m @45 m 1 u 5 m 2 a h 70 7b. LIA/E CLARENCE ANTON ANDERSON, OI ABILENE, KANSAS.

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Specification of Letters Patent.

Patented Jan. 1, 1918.

Application filed April 30, 1917. Serial No. 165,468.

To all whom it may concern:

Be it known that I. CLARENCE A. ANDER- sox, a citizen of the United States, residing at Abilene, in the county of Dickinson and State of Kansas, have invented certain new and useful Improvements in Telephone Toll Sets, of which the following is a specification. reference being bad therein to the accompanying drawing.

My invention relates to telephone exchange systems and more particularly to toll line connecting systems for small stations.

The object of my invention is to provide a simple and efiective combination and ar raugement of apparatus and circuits therefor for use in connecting toll lines to the switchboards of small or int mediate exchanges, and especially adapt to meet the requirements of telephone companies operating toll lines which must be connected to the small switchboards of privately owned exchanges where the service is dependent upon the class of equipment and the condition of the switchboard apparatus.

Another object of my invention is to provide a toll line connecting set of the above mentioned type assembled in the form of a.

unitary piece of apparatus adapted to be mounted on the side of a switchboard and having a leadin -in cable through which the various connections to the toll line and the switchboard circuits may be readily made without disturbing the circuit connections between the different elements of the toll .set

proper.

Other objects of my invention will be apparent from the following specification,

and accompanying drawings forming a part thereof.

My invention is illustrated in the accom panving drawings in which Figure 1 is a side view of my toll set assembled as a unit, the cover of the casin being removed to show the arrangement 0 the apparatus therein.

Fig. 2 is a front view of the casing showing the toll line signal and apparatuscontrol keys.

Fig. 3 is a perspective view. of a small switchboard with the toll set mounted on theside thereof.

Fig. 4 is a diagram of the circuit arrangement showing the signal bell connected across the toll line.

Fig. is a diagram of the circuit arrangement where the center checking plan is used.

Fig. 6 is a diagram showing the arrangement of the bell circuit where an open test is desired.

Fig. 7 is a diagram of the circuit arrangement where it is desired to shunt the bell with the condenser.

Referring in detail to the drawings, the unitary piece of apparatus comprising my toll set consists of a box or casing 15 adapted to be mounted on the side of a switchboard such as 16, which is provided with-the usual plugs, jacks, line signals, ringing and listening keys, and ringing generator, the operator being provided with a suitable head set not shown and which may be connected with the switchboard circuits through the jack 17 in a manner well known in the art.

Within the box 15 is mounted a repeating coil 18 secured as at 19 to a. board 20 remov-.

ably mounted on the back wall ofthe box-15. A pair of condensers 21 and 22 are mounted within-the box strapped to the rear wall by means of a suitable metal strap or bracket 14, the condenser 22 being in theform of a split condenser with a center connection which in effect divides it into two condenserelements as indicated at 23 and 24, Figs. 4

The drop signal 25 is mounted in the box with the shutter end projecting through the front wall 28 and below this and within the box are mounted the operators control keys 26 and 27,-the operating levers of which, 29 and 30 respectively, also extend through the front wall 28 on which they are mounted by means of the key plate 31. These keys are of a type well known in the art and so it is not deemed necessary to describe their structure in detail. It is to be pointedout, however, that the key 26 is so arranged that when the lever 29 is pushed downwardly, its operating roller 32 is moved upwardly to permit a pair of movable springs 33 and 34 to move upwardly into contact with the fixed pair of contact springs 35 and 36 respectively (see 1 and 4), at the same time tively, the springs 44 and 45 being ofi'set at 1 their ends, as shown in Fig. 1, to hold the key in its actuated position in the usual manner. The upper contacts 48 and 49 are arranged so that when the lever is thrown downwardly and the operating roller 43 moves upwardly, they will be moved out of contact with the contacts 50 and 51 and into contact with the contacts 52 and 53 respectively. As the contact springs of the control keys are arranged in pairs side by side, only on the front edge asl toll. From these binding posts the various connections are made to the toll line, bell and switchboard connections, these connections being brought out of the box through a suitable 'perforation in the bottom of the box as indicated in dotted lines at 68, Fig. 1. For tlie sake 'of clearness, these leads are omitted from Fig. 1, but when the device is mounted on a switchboard as indicated at 3, they preferably take the form of cables such as 69 and 72, the cable 72 containing a pair of con-.

ductors leading to the toll line and connected in multiple thereto, and the cable 69 containing pairs leading to theoperators plug and the listening common wires and ringing common wires of the switchboard, the pair terminating on the plug 70, being indicated in dotted lines at 71. The casing or box 15 is provided with a suitable cover 73. Suitable legends are placed on the front of the box as shown in Fig. 2, to indicate the manner of operating the key levers 29 and '30 to ring toll, listen, or ring the subscriber.

The circuit connections among the various apparatus elements are indicated diagrammatically in Fig.4 wherein the casing 15 is indicated in dotted lines in the form of a rectangle which includes all that portion of the diagram indicating the apparatus and circuit connections contained within the casing. The windings of the repeating coil 18 are indicated at 54, 55, 56 and 57, the windings 56 and 57 constituting a split primary winding, and the windings 54 and 55 the split secondary winding. The outer terminals of the primary coil are connected to the binding posts 7 and 8 from which conductors are led to the toll line and connected in multiple thereto. The inner terminals of the secondary coil members 56 and 57 are connected to the binding posts 10 and 11 respectively, to which are also connected the separate or outer" terminals of the condenser elements 23 and 24, respectively, of the split condenser. It will be seen that this connects the condenser elements 23 and 24 in series with the members 56 and 57 of the primary winding of the repeating coil. Connection is also made from the binding posts 10 and 11 to the contacts 35 and 33, respectively, of the key 26, which contacts when closed form a shunt around the condenser terminals. A bell 67 is connected across the outer terminals of the primary side of the repeating coil through the binding posts 7 and 8, and is thus connected in multiple with the toll line and the primary side of the repeating coil. The inner terminals of the members 54 and 55 of the secondary side'of the repeating coil are con- .nected to the terminals of the condenser 21' and to the contacts 36 and 34 so that the condenser 21 is connected in series with the secondary side of the repeating coil and will be shunted out of circuit upon the closure of the contacts 36 and 34. The drop 25 is connected in shunt with the condenser 21 and in series with the secondary side of the repeating coil. The outer terminals of the members 54 and 55 of the secondary side of the repeatingcoil are connected to the movable contacts 37 and 38 normally in contact with the fixed contacts 39 and 40 whichare connected in multiple to the contacts 4445 and 5051 of the key 30. The fixed listening contacts 46 and 47 are connected to the binding posts 5 and 6, respectively," from which binding posts conductors extend out of the casing 15 through a suitable cable as 69, Fig. 3, to the listening common wires in the switchboard. The pairs of stationary ringing contacts 4142 and 5253 are multipled to the binding posts 3 and 4 from .which conductors extend out of the casing to the common ringing wires of the switchboard. The movable contacts 48 and 49 are connected to binding posts 1 and 2- respectively, from which a pair of conductors lead to the terminals of the operators connecting plug 70, Figs. '3 and 4. The individual toll set plug is, of course, made to fit the jack of the particular switchboard to which, the toll set is to be connected.- In installing the set, the leads from. the binding posts 7 and 8 are preferably connected with the toll line through the usual lightning' protector not shown, while the bell 67 may be mounted in'any convenient place as on the side of the switchboard as shown in Fi 3 or on the toll-set casing.

en connecting a number of bridges across a toll line, the bridges must besufiiciently high to cause the ringing current to be effective and to this end I insert the conside' of the repeating coil. The] insertion of the condensers in the repeating coil windings would ordinarily lower the ringing efliciency of the coil, but this I overcome by denser elements '23 and 24 in the primary mounting the shunting contact springs 33-35 and 34-36 on the toll ringing key 26 and arranging them so that when the key is operated .o ring on the toll line the condensers 23-24 and 21 will. be short circuited thereby giving the repeating coil its full ringing efliciency.

In operation, upon receiving a call signal, the operator responds by throwing up the lever 30 of the listening and ringing key 27 to close the contacts 44-46 and 45-47 which connects her listening circuit, not shown, across the terminals of the secondary side of the repeating coil, which connection may be traced as follows: listening common wire to binding post 5, through contacts 46-44, contacts 39-37, repeating coil winding 54, condenser 21, winding 55, contacts 38-40, contacts 45-47, binding post 6 and back to the other listening common wire. The connection of the primary side of the repeating coil with the toll line may be traced as follows: one side of toll line to binding post 7 through winding 56, condenser elements 23 and 24, windin 57, binding post 8 and back to the other side of toll line. Upon ascertaining the number of the wanted subscribers line, the operator inserts the plug into the jack of the wanted line and rings the wanted party by throwing down the key lever 30 as directed by the legend R- Sub on the toll set, which opens contacts 48-50 and 49-51 and closes contacts 48-52 and 49-53. Thi connects the operators ringing common wires to the called line as follows: one of the ringing common wires to binding post 3, through contacts 52-48, binding post 1, out and back over called line by way of plug 70 andjack of called line, thence through binding post 2, contacts 49-53, binding post 4 to the other ringing common wire. At the end of the conversation the called party rings off by operating the clearing-out drop 25 of the toll set in the usual manner.-

The operator at the way-station switchboard may ring a bridged bell or bells on the toll line by pushing down the lever 29 as directecl by the legendR Toll on the toll set.

This operates the key 26 to close the contacts 37-41, 38-42, 33-35, and 34-36, the contacts 37-41 and 38-42 connecting the operators ringing common wires to the outer terminals of the secondary side of the repeating coil 54-55, the contacts 33-35 and 34'-36 shunting out condensers 10-11 and 21 respectively to increase the ringing efficiency of the repeating coil. I p

The circuit arrangement of Fig. 5 is identical with that of Fig. 4, except that the bell 67 is connected between ground and the binding post 9 which puts it in a grounded phantom. This is termed a center checking plan and is intended for use with toll lines connecting anumber of stations where it is erators at the way stations may ring a bridged bell at a center checking station in a manner similar to that described for Fig. 4.

Where it is desired to have the stations test open, to facilitate testing for trouble on the line, the bell 67 of each station is connected in shunt of one of the condenser elements 23-24 and in series with the other as indicated in Fig. 6, where" the terminals of the bell are shown connected to the binding posts 10 and 9. With this open test arrangement it is preferable to connect the bell at the last station in the manner indicated in Figs. 4 or 7 so that under normal conditions, the voltmeter reading will show that the line is up all the way to the last station. In Fig. 7 it will be noted, the bell is connected in shunt of condenser-elements 23-24 and in series with the repeating coil,

thus forming a path for direct current across Thus I have provided a novelarrange ment of circuits and apparatus adapted to be assembled in the form of a unitar device to be readily, operatively connected tween With I a toll line and a small switchboard such as the small switchboards of privately owned exchanges and the like, with no change in to be understood that this is for the purpose of definition only and that I contemplate all modifications thereof that may be made without departing from the spirit of the invention.

In this connection it is to be noted that as the function of the condensers is to increase the resistance of thebridges across the line to the passage of ringing current, .without affecting the efliciency of the repeating coil with currents of higher frequency, namely the talking currents, other elements subserving the same function may be used in their stead, such as a non-inductive resistance, and this. term non-inductive resistance in the claims, is to be construed as including either a closed circuit non-inductive resistance or a condenser, both of which as amatter of fact,

, a' specific embodiment of my invention, it is ofier a non-inductive resistance to the passagie of alternating current.

aving thus described my invention what I claim and desire to secure by Letters Patent is-' 1. In a telephone exchange system, a toll line, a repeating coil, a branch trunk line connected to said toll line through said reconnected to said toll line through said repeating coil, a condenser connected in series with each side of said repeating coil, a signaling device connected in shunt of the other of said condensers, meansfor connecting asource of ringing current to one side of said repeating coil, and means operable upon the operation of said connecting means to short circuit said condensers.

3. In a telephone exchange system, a toll line, a repeating coil, a branch trunk circuit connected to said toll line through said re. peating coil, a capacity connected in series with each side of said repeating coil, a .signaling device energized over the said toll line, a signaling device connected in shunt of one of "said capacities, means for connecting a source of ringing current to the terminals .of one side of said. repeating coil, and means operable upon the operation of said connecting means to short circuit said capacities.

4. A telephone exchange system, a toll line, a repeating coil, a branch trunk line connected to said toll line through said repeating coil, a capacity connected inseries with eachiside of said repeating coil, signaling means connected in shunt of one side of said repeating coil, means for connecting a source of ringlng current to the terminals of the other side of said repeatin coil, and means operable upon operation 0% said connecting means to short circuit said capacities.

5. In a telephone exchange system, a toll line, a repeatin coil, a branch trunk circuit connected to said toll line through said repeating coil, condensers connected in series with each side of said repeating coil, one of said condensers being divided into two condenser elements connected in series, a grounded signaling circuit phantomed on the toll line in series with said condensers and one side of said repeating coil, a signaling device connected in series with the other side of said coil, and means for connectin a source of ringing current to one side 0 said coil.

6. A toll set for connecting a toll line with the switchboard of a branch station comprising a casing adapted to be mounted on the side of a switchboard, a pedestal or board removably mounted on said casing, a repeating coil carried by said board, said repeating coil having its primary and secondary windings each split intermediate of its length to form four winding elements, terminal posts carried by said removable board and connected to the terminals of said winding elements, condensers mounted within said casing, 1 listening and ringing keys mounted within the box with controlling means therefor operable from the outside of said casing, a drop signal mounted within the casing with the signal display end proj ecting therethrough so as to be visible'from the outside, a plurality of binding posts mounted within the casing for interconnect ing certain of said elements contained in the casing with each other and with the toll line and switchboard, and a cover for said casing,

7. A tollset for efl'ecting connection between a toll" line and the usual listening, ringing and selective-switching circuits of a telephone switchboard, comprising a casing, a pedestal mounted within the casing and carrying a repeating coil and terminal posts therefor, condensers mounted within the casing and connected in series with the windings of the repeating coil, a signaling device mounted within the casing arranged to display a signal outside, of the casing and com nected in series with one side of the repeating coil, circuit control keys or I switches mounted within the casing with control leverstherefor operable from outside of the casing, a pair of trunking terminals for connection with the selectiveswitching circuit of the switchboard, a pair of ringing terminals for connection with the ringing circuit of the switchboard, a pair of listening terminals for connection with the listening circuit of the switchboard, a pair of toll line terminals for connection with the toll line, said terminals being mounted within the casing, circuit connections normally 0011- necting said trunking terminals with the secondary winding of said repeating coil, circuit connections normally connecting said toll line terminals with the primary circuit of said repeating coil, contacts on one of said control keys operable to simultaneously 7 open the said connection between the trunking terminals and the repeating coil, to short circuit said condensers, and to connect said ringing terminals with the secondary winding of the repeating coil, contacts on one of said keys operable simultaneously to open the said connection between said trunk terminals and the repeating coil and close a connection between said trunking terminals and said ringing terminals, and contacts on one of said keys operable independently of the aforesaid contacts to connect said listen- 8. A tall set for eflecting connection between a toll line and the usual listening, ringing and selective-switching circuits of a telephone switchboard, comprisin a'casing containing a repeating coil, con ensers, "a

drop signal, circuit controlling keys and connecting terminals, said connectin terminals being arranged for connection with the toll line and the listening, ringing and selectiveswitching circuits of the switchboard, and said circuit controlling keys being arranged and connected for controlling electrical connectionsbetween said apparatus and circuits.

9. In combination with a telephone switchboard havin line'and connective terminals, a self-contained unitary toll line terminal set comprising a connective terminal ada ted to connect the toll line with line termina s on the switchboard, a signal, and listening and ringing means adapted to work over the toll hne in one direction and a connected subscribers line in the other, together with a casini; for said toll set, a set of circuit termina s on said casing and connections from said terminals to the several operative elements of the set, including the signal, whereby said signal and other elements may be transposed, shifted or otherwise changed to accommodate the set to any desired plan of working the toll service and line connections.

10. In a telephone exchange system, a toll line, a repeatin coil, a branch trunk line connected to said toll line through said repeating coil, a non-inductive resistance in series with each side of said repeating coil, means for connecting ringing current to one side of said repeating coil, and means operable upon the operation of said connecting. means to shunt out said resistances.

In testimony whereof I aflix my signature.

CLARENCE ANTON ANDERSON. 

